Introduction

As promised, today we’re here to take a look at the performance of ATI’s RADEON X800 PRO with Intel Pentium 4 processors. Based on our preview from the beginning of this month, we already know the X800 PRO is fast, nearly doubling the performance of RADEON 9800 XT, and at a price point that is $100 less than ATI’s high-end RADEON X800 XT Platinum Edition. This performance is provided by its 12-pipeline R420 core, which is clocked at 475MHz and its 256-bit memory interface operating at 900MHz.

With all this graphics horsepower however, there are cases where the X800 PRO is held up by the performance of the CPU in the system. We saw this repeatedly in Epic’s latest shooter, Unreal Tournament 2004, and in other titles such Splinter Cell and even Far Cry. In these cases performance was the same across multiple graphics settings and screen resolutions.

Being CPU-limited isn’t necessarily a bad thing. From an optimists’ viewpoint, eye candy features such as anti-aliasing and anisotropic filtering are “free”, meaning they come with no performance hit. You can also crank up the texture and geometry detail and screen resolution with little or no drop in performance. All of these settings combined produce an excellent picture. The downside is frame rate; with a faster CPU you could have all the visuals cranked up to their maximums and achieve higher performance. Basically, you aren’t getting the most bang from your buck.

This situation is exacerbated by the fact that for the most part, the RADEON X800 visually looks the same as its predecessors. ATI has improved the efficiency of its SMOOTHVISION engine in RADEON X800, including support for new resolutions, but little else has changed. In fact, when the anisotropic filtering “cheating” fiasco broke a week ago, one of ATI’s defenses was that they’d merely adopted the RADEON 9600’s filtering algorithm. And regarding the RADEON X800’s other new features, temporal AA and 3Dc, both of these could potentially be integrated into existing RADEON cards like the RADEON 9800 XT, albeit with slightly lesser quality in the case of 3Dc. In fact, ATI is expected to incorporate temporal AA for all DX9 cards in an upcoming CATALYST release.

These factors make the upgrade decision a tough one. Do you pair your Pentium 4 2.4GHz with a RADEON X800 PRO even though it’s likely to be CPU-bound in a lot of cases? Or perhaps you should save a little money and get the RADEON 9800 XT instead? How much of a performance difference would you see between the two? Hopefully this article will help you answer these types of questions in addition to highlighting the processor crossover point, where the higher clock speeds are able to feed the X800 PRO more sufficiently.

The processors

Once again we wanted to include the widest range of clock frequencies possible. To keep things simple, we focused mainly on the 800MHz “C” processors from Intel, but we also included a 2.0A Northwood Pentium 4 chip to represent the slower processors. We wanted to include a 3.4GHz Pentium 4, but our Prescott processor wasn’t properly recognized by any of our motherboards. Since it’s an engineering sample with an unlocked multiplier, it’s a little different than your typical Prescott 3.4GHz processor. None of the motherboards recognized its 17.0 multiplier, running it at 14.0 instead in all cases. As soon as we get this resolved we’ll update the article with 3.4GHz numbers.